Method of making honed guides



Aug. 2, 1938. E. s. EPLETT METHOD MAKING HONED GUIDES Filed Jan. 5, 1937fizzrzziar: (5

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Patented Aug. 2, 1938 PATENT OFFICE METHOD OF MAKING HONED GUIDESEmanuel S. Eplett, Michigan City, Ind., assignor to Sullivan MachineryCompany, a corporation 7 of Massachusetts 7 Application January 5, 1937,Serial No. 119,107

4 Claims.

My invention relates to methods of making parts having honed bores andtraversed by lateral openings, as,- for example, crosshead guides,ported cylinder liners, etc.

In the making of parts which are to be honed, it is necessary that thereshall be no openings in the surface to be honed of such size or locationas to permit any tendency towards catching of the hone during the honingoperation. In the formation of guide or other cylindrical elementswithin which parts are to move reciprocably, or oscillate, or both, ithas been found that'if the cylindrical finished guide surface is firstformed, and thereafter a'substantial section of metal is removed and anopening formed through the finished cylindrical surface, there is veryapt to be a'warping of the remaining portions of the cylindrical surfacein View of the internal rearrangements of the strains within theguide-forming member. I have found, however, that by nearly severing theportion to be ultimately removed, by an operation which does not formobjectionable openings extending through the surface to be honed, honingthe surface to be so treated, and then removing the thin web of metalwhich has been left to hold the portion to be removed in place, it ispossible to form a guide or like member which'will be nearly perfectlycylindrical atthe conclusion of its manufacture, and will not 'besubject to a material warping tendency:

An object of my invention is to provide an improved method of making apart having a honed bore and one or more lateral openings. Anotherobject of myinvention is to provide an improved method of making a honedcrosshead guide having an opening in its side. A further object of myinventionis to provide an improved method of providing a virtuallyperfectly cylindrical guiding surface upon a part which is traversed byone or more lateral openings. Other objects and advantages of myinvention will hereinafter more fully appear.

In the accompanying drawing, which includes certain views which will beof assistance in understanding the illustrative mode of practice of myinvention,- I 1 Fig. 1 is a View, with parts broken away, in centralsection through a compressor in which a guide element constructed inaccordance with my invention is embodied.

Fig. 2 is a perspective view of a casting from which a guide is to beformed by certain operations thereon.

Fig. 2a is a section through the casting of Fig. 2, midway between theends of the latter, taken perpendicular to its axis, on a reduced scale.

Fig. 3 is another perspective view of the same casting after the samehas been prepared for honing.

Fig. 3a is a section through the structure of Fig. 3, taken similarly toFig. 2a, and also reduced.

Fig. 4 is a persective view of the completely finished guide member.

Referring to Fig. 1, it will be observed that a compressor or pump,generally designated I, is provided with a flywheel 2 mounted upon acrank shaft 3, and the latter is operatively connected, by a connectingrod 4, to a crosshead pin 5 supported in a cylindrical crosshead element6. The crosshead element is connected by a suitable rod 1 with the partsto be actuat-edfor example, the piston of the compressor or pump. Thecrosshead 6 is reciprocable in a crosshead guide 8 of the liner type,this crosshead guide element being centered by cylindrical surfaces Illand II within the frame I2 of the compressor. A suitable hand andinspection hole, designated I4 in Fig. 4, is provided to permitinspection of the crosshead and guide structure, and access to thecrosshead.

The liner type crosshead guide 8 is formed from a casting such as isshown in Figs. 2 and 20., generally designated I5, and suitably ribbed,as at I6, throughout a substantial portion of its periphery forstiffness and strength. A flange I! 1 traversed by bolt holes [8 isarranged at one end of the crosshead guide for securing the same inposition. The casting I5 is hollow from end to end, before thecommencement of machining operations upon it. As a desirable first step,while it is understood that the sequence of steps is subject tovariation, the casting I5 may be turned to provide the surfaces I0 andII, which will serve to center it. The flange I! may be turned andprovided with the bolt holes I8. Casting I5 will then be rough-bored,and counterbored or grooved, as at IS. The portion 20 of the castingwhich is to be cut away to provide the opening I4 will then be subjectedto what may be termed a profiling operation, a milling cutter beingemployed to cut around the designed opening or openings, these cuts,however, not being made completely through the peripheral wall of themember I5, but instead stopping just short, perhaps an eighth or asixteenth of an inch or soalthough a considerable variation ispermissible, of cutting through into the bore of the member I5. Thismilling operation surrounds the portion 20--of which only one is shownhere, although there may be otherswith a narrow groove 2!; and becauseonly a thin web of metal remains connecting the portion 2!] with thebody of the member l5, there will promptly be an in ternal rearrangementof the strains within the 5 member I5 and the member [5 will attainapproximately the shape which it will have in its finished form. Afterthis strain-rearrangement has taken place, the interior guide surface 22of the guide member will be honed by a suitable hone, and a highlyfinished cylindrical surface produced. Finally, a milling cutter willagain be employed in cutting away the thin web of metal holding the part26 in position in the member I 5, the member 26 being removed and thefinish-ed guide thereby made complete.

It is to be understood, of course, that diametrically opposite portionsmay be removed from the sides of the cylindrical guide, and it will befurther understood that this same method of manufacture could be appliedto the cylinders of engines in which ported walls-liners orintegral-traversed by the piston, will be desired. Other uses of thisimproved method will also suggest'themselves to those skilled in theart. It

will be evident that it would be possible, under some circumstances andwith certain forms of honing devices, to make the end cuts-that is,those extending circumferentially of the element underconstruction-completely through, and

(39 thereby allow an even more perfect rearrangement of internalstresses.

To summarize, it will be noted that in the illustrative mode of applyingmy invention described, a suitable cast or otherwise producedcylindrical blank has its external mounting surfaces suitably turned andits interior bored. The portions which are ultimately to be removed fromthe wall which is to provide a cylindrical guide surface, are then cutaround to such a degree and in such manner as to enable the nearestpossible approximation to the ultimate struc-- ture of the device,without creating conditions inimical to successful honing. The bore ofthe part is then honed, and thereafter, as by a mill- 45 ing cutter, theremaining attachments of the portions which are to be removed aresevered and, with any dressing of the edges of these openings which maybe desired or needed, the guide is completed.

My improved method has been employed with much success in themanufacture of crosshead guides for compressors, and nearly perfectlycylindrical guides having highly finished honed surfaces are produced,and these are relatively free 55 from unneutralized internal stresseswhich would result in a deformation of the cylindrical guiding surfacesubsequent to the installation of the guide element in its assembledrelation in a machine.

From the foregoing description, it will be evident that I have providedan improved method of making cylindrical guides or other parts. It willbe evident that the same is not limited to the formation of trulycylindrical bores, however. It will be noted, moreover, that I haveprovided an improved method which results in no difficulties inmachining, and at the same time results in a finished part virtuallyfree from any,

tendency to subsequent deformation due to portions thereof having beencut out after the final honing operation was performed.

While I have in this application specifically described one iilustrativemethod in which my invention may be employed, it will be understood thatthis method is shown for purposes of illustration, and that theinvention may be modified and embodied in various other methods withoutdeparting from its spirit or the scope of the appended claims.

What I claim as new and desire to secure by Letters Patent is: a

1. The method of forming cylindrical-guidesurface-providing parts whichhave openingtraversed, bored and honed guide surfaces, which includes,between the boring and honing of said parts the step of nearly severingfrom the adjacent material, any portions which are to be removed toprovide openings,

2. The method of making cylindrical guide members or the like, whichincludes the steps of externally turning the same as needed, roughboringthe same, partially severing any portions of thecylindrical-guide-providing wall which may ultimately have to beremoved, honing the roughbored bore, and then completing the severing ofthe wall portions to be ultimately removed.

3. The method of forming cylindrical-guidingsurface-providing memberswhich includes rough-boring, cutting nearly through from the outside tosaid rough bore the Wall of said member around any portions of said wallwhich are ultimately to be removed, honing said bore after the strainsin said member have again reached a state of equilibrium, and thencompletely severing the portions to be removed.

4. The method of making a cylindrical-guide-- providing member whichincludes forming the positioning surface or surfaces of said member,boring said member, cutting away the material surrounding any portionsof the wall of said member which are ultimately to be removed, in amanner to nearly sever said portion or portions while leaving theinternal surface of said guide free of openings likely to cause honebreakage, 1,

honing the bore of said member, and then completing the severing of theparts to be removed from its wall.

EMANUEL S. EPLETT.

WNW

Will

